Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For valacyclovir, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to valacyclovir or acyclovir. Also tell your health care professional if you are allergic to any other substances, such as foods, sulfites or other preservatives, or dyes.

Pregnancy—Adequate and well-controlled studies in humans have not been done with valacyclovir or acyclovir. However, acyclovir has been used in pregnant women and has not been reported to cause birth defects or other problems.

Breast-feeding—It is not known whether valacyclovir passes into breast milk. However, acyclovir does pass into breast milk but has not been reported to cause problems in nursing babies.

Children—Studies on this medicine have been done only in adult patients. There is no specific information comparing use of valacyclovir in children with use in other age groups.

Older adults—Valacyclovir has been used in elderly patients and has not been shown to cause different side effects or problems in older people than it does in younger adults. Elderly patients are at a high risk for dehydration and should drink plenty of fluids.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change your dose or other precautions may be necessary. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other medical problems—The presence of other medical problems may affect the use of valacyclovir. Make sure you tell your doctor if you have any other medical problems, especially:

• Advanced human immunodeficiency virus (HIV) infection or
• Bone marrow transplantation or
• Kidney transplantation—Patients with these medical problems may have an increased risk of severe side effects

• Kidney disease—Kidney disease may increase blood levels of this medicine, increasing the chance of side effects